ARM: 9483/1: select HAVE_POSIX_CPU_TIMERS_TASK_WORK

Commit c6e61c06d606 ("ARM: 9463/1: Allow to enable RT") enabled PREEMPT_RT
on ARM but did not select HAVE_POSIX_CPU_TIMERS_TASK_WORK. This leaves
CONFIG_POSIX_CPU_TIMERS_TASK_WORK disabled, so CPU timers expire in hard
IRQ context.

On PREEMPT_RT this makes run_posix_cpu_timers() take the sleeping
sighand->siglock:

  BUG: sleeping function called from invalid context at spinlock_rt.c:48
    rt_spin_lock from lock_task_sighand
    lock_task_sighand from run_posix_cpu_timers
    run_posix_cpu_timers from update_process_times

ARM handles TIF_NOTIFY_RESUME on all return-to-user paths, including v7-M.
ARM32 KVM host support was removed by commit 541ad0150ca4 ("arm: Remove
32bit KVM host support"), so the select need not be conditional on KVM.

Select it to defer POSIX CPU timer expiry to task context.

Reproduced with setrlimit(RLIMIT_CPU, ...) and a busy loop. The same path
is used by setitimer(ITIMER_PROF or ITIMER_VIRTUAL) and POSIX CPU timers
created with timer_create().

Assisted-by: Claude:claude-fable-5

Fixes: c6e61c06d606 ("ARM: 9463/1: Allow to enable RT")
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

0 files changed, 0 insertions, 0 deletions